Commit 5ae5dc96 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

INSTALL: clarify 386 and no-sse2 options. 



Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
parent 76f572ed

Configure

+3 −2
Original line number Diff line number Diff line
@@ -60,11 +60,12 @@ my $usage="Usage: Configure [no-<cipher> ...] [enable-<cipher> ...] [-Dxxx] [-lx 
# zlib-dynamic	Like "zlib", but the zlib library is expected to be a shared

#		library and will be loaded in run-time by the OpenSSL library.

# sctp          include SCTP support

# 386           generate 80386 code

# enable-weak-ssl-ciphers

#               Enable weak ciphers that are disabled by default. This currently

#               only includes RC4 based ciphers.

# no-sse2	disables IA-32 SSE2 code, above option implies no-sse2

# 386           generate 80386 code in assembly modules

# no-sse2       disables IA-32 SSE2 code in assembly modules, the above

#               mentioned '386' option implies this one

# no-<cipher>   build without specified algorithm (rsa, idea, rc5, ...)

# -<xxx> +<xxx> compiler options are passed through

# -static       while -static is also a pass-through compiler option (and

INSTALL

+25 −19
Original line number Diff line number Diff line
@@ -383,19 +383,19 @@ 
                   Don't build SRTP support



  no-sse2

                   Exclude SSE2 code paths. Normally SSE2 extension is

                   detected at run-time, but the decision whether or not the

                   machine code will be executed is taken solely on CPU

                   capability vector. This means that if you happen to run OS

                   kernel which does not support SSE2 extension on Intel P4

                   processor, then your application might be exposed to

                   "illegal instruction" exception. There might be a way

                   to enable support in kernel, e.g. FreeBSD kernel can be

                   compiled with CPU_ENABLE_SSE, and there is a way to

                   disengage SSE2 code paths upon application start-up,

                   but if you aim for wider "audience" running such kernel,

                   consider no-sse2. Both the 386 and no-asm options imply

                   no-sse2.

                   Exclude SSE2 code paths from 32-bit x86 assembly modules.

                   Normally SSE2 extension is detected at run-time, but the

                   decision whether or not the machine code will be executed

                   is taken solely on CPU capability vector. This means that

                   if you happen to run OS kernel which does not support SSE2

                   extension on Intel P4 processor, then your application

                   might be exposed to "illegal instruction" exception.

                   There might be a way to enable support in kernel, e.g.

                   FreeBSD kernel can  be compiled with CPU_ENABLE_SSE, and

                   there is a way to disengage SSE2 code paths upon application

                   start-up, but if you aim for wider "audience" running

                   such kernel, consider no-sse2. Both the 386 and

                   no-asm options imply no-sse2.



  enable-ssl-trace

                   Build with the SSL Trace capabilities (adds the "-trace"
@@ -458,11 +458,12 @@ 
                   where loading of shared libraries is supported.



  386

                   On Intel hardware, use the 80386 instruction set only

                   (the default x86 code is more efficient, but requires at

                   least a 486). Note: Use compiler flags for any other CPU

                   specific configuration, e.g. "-m32" to build x86 code on

                   an x64 system.

                   In 32-bit x86 builds, when generating assembly modules,

                   use the 80386 instruction set only (the default x86 code

                   is more efficient, but requires at least a 486). Note:

                   This doesn't affect code generated by compiler, you're

                   likely to complement configuration command line with

                   suitable compiler-specific option.



  enable-tls1_3

                   TODO(TLS1.3): Make this enabled by default
@@ -500,7 +501,12 @@ 
                   These system specific options will be passed through to the

                   compiler to allow you to define preprocessor symbols, specify

                   additional libraries, library directories or other compiler

                   options.

                   options. It might be worth noting that some compilers

                   generate code specifically for processor the compiler

                   currently executes on. This is not necessarily what you might

                   have in mind, since it might be unsuitable for execution on

                   other, typically older, processor. Consult your compiler

                   documentation.





 Installation in Detail